Flashing and regulating apparatus for discharge-tube display



March 13 1928.

F. HOTCHNER FLASHING AND REGULATING APPARATUS FOR DISCHARGE TUBE DISPLAY Filed March 1927 IO il il I! l Ill li m IINVENTQR mesa-d Mar. 13, 192s. v

UNITED STATES PATENT- OFFICE.

FRED HOTCHNER, OI IDS ANGELES, CAL'lJ'OBNlIA.

Application filed much 9, 1921. Serial in. 174,063.

This invention relates to electric displays of the discharge tube type made into electric signs, building ornamentation, stage effects, etc. It provides means and apparatus for illuminating, regulating the'current flow in and flashing such displays, said means overcomin the disadvanta es now met due to the inl ierent electrical dharacteristics of dis-' charge tubes, reducing the cost, improving the efiects, simplifyin and increasing the range of application 0 such displays.

Discharge tube installations as now made are ve cumbersome and expensive and greatly imited in their applications as compared with incandescent lamp installations.

his is due to the limitations arising from the characteristics of the tubes. The most important characteristics of discharge tubes are as follows:

The variable resistance of the tube'over a single cycle. I

he variable resistance of the tube over the eriod of its life.

T e capacity'efiect energyof ionlzation.

'Thedistributed capacity effect due to the in the tube due to the conductivity of the walls. n

. The tendency of the arc to pinch out.

These characteristics and certain conditions met in practice give rise to numerous difiiculties met in the assembling of a number of tubes into a display.

. In practice the variation between several tubes in the same display is enormous. No two tubes will be the same in their electrical characteristics even if. made the. same and at the same time. As the tubes are bent into the shape of letters and figures the cross sections are not uniform.

The length varies and the configuration is such as to cause stat i to and inductive efiects that can not be meas- 'in parallel ured and are always different. Tubes conare used together.

taining difierent gases Tubes of different age will be found together in the same display. It can be easily underts at balancin cr -compenects of the to es have all Attempts at operating a number of tubes have also been made w1thout success. As the'tube's hold a certain amount of v energy during the cycle ofcurrentchange l te -bet'ween it is to be expected t at currents will. circuthe tubes. This appears to be the evidence of the experiments suethe casefrom and might easily be the reason w A CIGESBS.

ect as surges on transmission lines. Voltage peaks ,will exist that will rupture condensers and break down the insulation. As oscillation is easily set up no matter how carefully" designed a 'parallel system might be; if one of the many varia les changes, two or more tubes might start to oscillate. .As I explai'nblow, in this invention the use of inductances or .capacitances has been dispensed with, thereby eliminating anything that tends to exaggersu press oscillations.

ecause of the variable resistancelof the tubes during a cycle of current change the electrical problems involved are unusually dlflicult. The resistance of the tube is very high before current flow starts,.and as soon .as current flows the resistance falls to a very l low value, so low 1n tential to be maintain damaged by the current. The method of opcrating discharge tubes in practice at the fact, that were the po ed after the are started the tube would be destroyed or seriously ate the oscillating efiect; andtl 'e regulating device used has in itself "a 'certain power to present time .is to place a single tube or sev,-

eral tubes in. series on a single transformer of such poor characteristics that the potential across the terminals falls as the current in- Somewhat the same effect is also secured by using a transformer of characteristics approachmg that of standard power transformers and inserting a choke. coil in the system, preferably in series with the primary. parallel operation is impossible as the tube which strikes anarc first will immediately lower the potential acrossthe other tubes below the arcing voltage and will also draw anexcessive current.

The oh'ects of my'inv'ention, therefore, are to provi e means ofoperating a-number of tubes in parallel which may be of any desired length, of any current requirements and have any inductive or static characteristics incidental to its manufacture.

Another object is to prevent oscillations between the tubes and dangerous rises of It is obvious that on such a current source A further object is to reduce the expensive insulation required for high voltage operation by placing tubes in parallel and operating at a lower volta e.

A further object is to make use of transformers of characteristics approaching those of standard ower transformers.

Another 0 ject is to provide means of flashing the tubes separately on a parallel operating system.

Further objects will appear as the description proceeds.

Fig. 1 is a diagram showing the principal features of this invention.

Fig. 2 shows a modification of this invention 1n which I use a tap on the transformer for lighting the filaments instead of a separate transformer.

Fig. 3 shows a further modification of this invention in which I distribute the tubes into two sets, each set working on one side of the cycle.

I tubes thus comple .of the half-wave rectifying In the drawings, numerals 2, 3, 4 and 5, Fig. 1, are discharge tubes which may be of any length desired or of any configuration. They may also be of different current characteristics or may contain different gases. Numerals 6, 7, 8 and 9 are thermionic tubes type. Each thermionic tube has a plate 14, 15, 16 and 17 which is connected to one terminal of the correspondin dischar e tube by the wires 10 11, 12 13. Eac thermionic tube has a filament, 18, 19, 20 and 21, one terminal of each filament being connected to the wire 22 which extends to one terminal of the second a 23 of the s'te -up transformer 24. The otlier terminal 0 the secondary 23 connects to the common return wire to one terminal on each of the discharge ting the parallel circuit.

The filament lighting c1rcuit.is thru the filaments and the wire 22 which connects to one terminal of the filament transformer secondary 26, the wire 28 which extends to the collector brush 29 of the flasher 30, the

wires 31, 32, 33 and 34 connecting to the flashing brushes 35, 36, 37 and 38 and ex-.

tending to the other terminals of the fila-v ments 18, 19, 20 and 21, thru the variable resistances 39, 40, 41 and 42.

In practice the transformer 24 is design to develop a voltage hi h enough to light the longest tube that would be used, and to pass e maximum current that it will be operated for with as little drop across the terminals as is consistent with of grovidin transformers. of high rop, or of 'gh cho 'ng effect.

When the display is installed each variable resistance is a justeduntil its corresponding discharge-tube is at the 'ght degree of illumination. As the current passing thru the discharge tube is dependent on the elec- 25 which extends f good design. Thls is in contrast with the present (practice If the tubes change by a e the resistances are readjusted and t e isp ay brought back to normal.

Should a short circuit occur in the tube, or across the tube terminals the thermionic tube continues to serve as a regulator and 'protects the transformer from a rush of current.

As current can flow only in one direction thru the thermionic tube, oscillations between the tubes can not occur as oscillations to have any effect must be sustained longer than one half cycle.

By designing the transformer with a minimum of choking effect the tendency to oscillate is further reduced.

The operation of the flasher 30 illuminates and extm ishes the filaments of the thermionic tu s. When the electron flow is interrupted the current to the discharge tube is cut off without an arc. The flashing tube does not disturb any of the others, and all tubes will burn the same re ardless of how many others are li hted. This method of flashing is a decide improvement over the present practice which is to put the different tubes that are to be flashed on separate transformers and flash the primaries. The current interru ted by my flasher is very small as compare with the power interrupted and ihelburn on the brushes will therefore be very itt e.

While I have shown a separate transormer in Fig. 1 for the illumination of the filaments, this is not necessary as a tap 43, Fig. 2 can be taken off of the secondary 23 to provide the low potential current for the filaments. Another method would be to provide an extra coil on the same core as the secondary 23.

In Fi 3 I show a'modification of this invention in which the tubes are divided into two groups and each roup is connected to work on one half of t e c cle, thus making use of the entire output 0 the transformer. The discharge tubes 44 and 45 are connected in series each with one of the thermionic tubes 46 and 47 and the resistances 48 and 49 on one side of the system. They are carried thru the'flasher 50 and to the tap 51 on one side of the secondary 52 of the transformer 53. The tubes 54 and 55 are connected in series with the regulating tubes 56 and 57 and the resistances 58 and 59 and thru the flasher 60 to the tap 61.

Having thus described my invention and the manner of constructing and using the same, altho without attempting to set forth all of the forms in which it ma be made, or all of the modes of its use, I clhim:

tube in series with a thertube, said regulating tube 1 having a plate and a filament; and means of thermionic regulating regulating the temperature of said filament.

1. A discharge tube in series with a thermionic regulating tube, said regulating tube having a plate and a filament;v and means of flashing said filament.

5. A discharge tube in series with a thermionic regulating tube and means to impress an alternating potential across both said tubes, said potential maintaining the sine wave independently of the current flowing thru said tubes.

6. A plurality of discharge tubes, each in series with a thermionic regulating tube and all of said series of tubes being in parallel.

7 A plurality of discharge tubes, each in series with-a thermionic regulating tube of the half-wave rectifying type, and all of said series of tubes being in parallel.

8. A' plurality of discharge tubes, each of said discharge tubes being in series with a tube, all of said series of tubes being in parallel; each of said thermionic tubes having a plate and a filament and means to regula'tethe temperature of each, of said filaments independently.

9. A plurality of discharge tubes, each of said discharge tubes being in series with a thermionic regulating tube and all of said series of tubes being in parallel; each of said regulating tubes having a plate and a filament and means of flashing said filaments independently.

10. A plurality of discharge tubes, each in series with a thermionic regulating tube and means to impress an alternating potential across all of said series of tubes,-the. source of said potential maintaining said potential in substantially a sine wave form regardless of the performance of said tubes.

11. A plurality of discharge tubes in parallel and means to suppress oscillations between said tubes.

12. A plurality of discharge tubes in parallel, means to flash said discharge tubes independently and means to suppress oscillations between said tubes.

13. A discharge tube and non-inductive, non-capacitive means to regulate the current passing thru said tube. y

14. A plurality of discharge tubes in parand connected to work allel and separate non-inductive, non-capacitive means in series with each of said tubes to regulate the current passing thru each of said tubes independently.

15. A plurality of discharge tubes, each tube being in series with a regulating thermionic tube and all of said sets of tubes being in parallel on the secondary of a step up transformer, and means to interrupt the flow of electrons in any one or more of said thermionic tubes to extinguish the corresponding discharge tube or tubes.

16. A plurality of discharge tubes of different current consumption, each of said tubes being in series with a thermionic regulating tube and all of said series being in arallel.

17 The method of operating discharge tubes in parallel which consists of connecting a plurality of discharge tubes, each of said tubes being in series with a thermionic regulating tube, in parallel across a source of current that maintains a relativel true sine Wave of potential across the terminals of all of said series of tubes.

18. The method of operating discharge tubes in parallel which consists of connecting in series with each of saidtubes means to limit the flow of current to a maximum value and to one direction only.

.19. A plurality of discharge tubes, each of said discharge tubes being in series with a thermionic regulatin tube of the hot filament type and all of sand series being in parallel across the terminals of a high-voltage transformer, and a low voltage transformer connected with the circuit of said high voltage transformer for illuminating the filaments of said thermionic'regulating tubes.

1 20. A plurality of discharge tubes, each of said discharge tubes being in series with a thermionic regulating tube of the hot filament type and all of said series being in parallel across the terminals of a high-voltage transformer, and means in said transformer to provide a current of low potential for illuminating the filaments of said thermionic regulating tubes.

21. A plurality of discharge tubes, each in series with a half-wave rectifying regulator, and all of said series being in paral el, said series being divided into two groups on opposite sides of the cycle.

Signed at Los Angeles, California, this 4th day of March, 1927.

FRED-HOTCHNER,

10hrv 

